Counterbalance assembly



Aug. 10, 1965 G. A. SMITH COUNTERBALANGE ASSEMBLY 3 Sheets-Sheet 1 Filed Dec. 21, 1962 ATTORNEY Aug. 10, 1965 G. A. SMITH 3,199,914

COUNTERBALANCE ASSEMBLY Filed Dec. 21, 1962 3 Sheets-Sheet 2 INVENTOR.

ATTORNEY Aug. 10, 1965 G. A. SMITH 3,199,914 COUNTERBALANCE ASSEMBLY Filed Dec. 21, 1962 5 Sheets-Sheet s INVENTOR.

ATTORNEY United States Patent 3,199,914 COUNTERBALANCE ASSEMBLY Glen A. Smith, Birmingham, Mich, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Dec. 21, 1962, Ser. No. 247,472 7 Claims. (Cl. 296-106) This invention relates to counterbalance assemblies and more particularly to counterbalance assemblies for swingable vehicle closures. This application is a continuationin-part of applicants copending application Serial No. 155,146, filed November 27, 1961, and since abandoned.

The counterbalance assembly of this invention is particularly adapted for use with vertically swingable station wagon lift gates and provides a very simple and efficient structure which counterbalances the lift gate in its open position and also aids the operator in moving the lift gate to this position. Generally, the counterbalance assembly includes a pair of foldable toggles each located between a pair of juxtaposed side walls of the closure and of the body, with each toggle comprising a link pivoted to the body wall adjacent one end thereof and pivoted adjacent its other end thereof .to a torque rod or member crank portion which is swingable relative to one wall of the lift gate about the axis of the torque rod. The torque rods or members are located within the lift gate and are anchored to the lift gate adjacent the wall opposite the wall relative to which the crank portion swings. When the lift gate is moved to an open position, the toggles unfold to aid the operator in raising the lift gate. When the lift gate is in its open position, the toggles are only partially unfolded and provide support struts for holding the lift gate in this position.

The primary object of this invention is to provide a new and improved counterbalance assembly. Another object of this invention is .to provide a new and improved counterbalance assembly for swingable vehicle closures which aids the opera-tor in moving the closure to an open position and provides a supporting means for the closure in its open position. A further object of this invention is to provide an improved counterbalance assembly for ver tically swinging station wagon lift gates which aids the operator in moving the lift gate to an open position and also provides a support strut for holding the lift gate in this position.

These and other objects of the invention will be readily apparent from the following specification and drawings wherein:

FIGURE 1 is a partial rear elevational view of a station wagon having a lift gate and embodying a counterbalance assembly according to one embodiment of this invention;

FIGURE 2 is an enlarged partially broken away view of a portion of FIGURE 1;

FIGURE 3 is a view taken generally along the plane indicated by line 3-3 of FIGURE 2;

FIGURE 4 is a view similar to FIGURE 3 showing the lift gate in open position;

FIGURE 5 is a perspective view of the torque rods or members;

FIGURE 6 is a view similar to FIGURE 3 showing another embodiment of this invention, with the lift gate being shown in closed position;

FIGURE 7 is a view similar to FIGURE 6 showing the lift gate in open position, and

FIGURE 8 is an enlarged perspective View of a portion of FIGURE 6.

Referring now particularly to FIGURE 1 of the draw ings, .a vehicle body 10 of the station wagon type includes a rear opening 12 which is opened and closed by a lift gate 14 swingably mounted adjacent its upper edge on the body it} by suitable hinge means 16, such. as shown in FIGURE 3, for movement between a closed position, as shown in FIGURES l and 3, and an open position, as shown in FIGURE 4. The lift gate 14 is counterbalanced by a counterbalance assembly according to one embodiment of this invention which will now be described.

A pair of torque rods or members 18 and 26 are located within the lift gate 14, with the torque rods including laterally bent anchor end portions 22 and 24, respectively, which are anchored respectively to the opposite side walls 26 and 23 ofthe lift gate by anchor brackets 36. Torque rod 13 extends outwardly of the lift gate through an opening in wall 23 and is journaled adjacent the wall in a bushing 31 supported by a bracket 32 secured to the inner-surface of the wall. Likewise, torque rod 26 extends outwardly of the lift gate through an opening in wall 26 and is journaled adjacent the wall in a bushing 34 mounted in a bracket 36 secured to the inner surface of wall 26. The torque rods are provided with respective flattened crank portions 38 and 4%, which are swingable relative to respective walls 28 and 26 about the axis of the torque rods 1% and 29 during opening and closing movement of the lift gate. The upper ends of the crank portions 53 and 4d are pivoted at 42 to links 44, the lower ends of which are pivoted at 46 to brackets 4-3 which are secured to the body side walls 56 and 52 juxtaposed to the lift gate side walls 26 and 28, respectively.

As shown schematically in FIGURE 5, the torque rods lfiand 29 are each wound up with respect to their anchor end portions 22 and 24, respectively, to bias the crank portions 33 and 4t} thereof inwardly and downwardly of the opening 12 or counterclockwise, as viewed in FlG- URES 3 and 4. When the lift gate 14is in a closed position, as shown in FIGURES 1, 2 and 3, the crank portions 38 and 4t and their respective links 44 are laterally aligned and are located within the space between the juxtaposed side walls 26 and 23 of the lift gate and the respective walls 50 and 52 of the body. When the lift gate is moved to an open position, the links 44 are swung downwardly and outwardly of the body opening as the torque rods 18 and 2t) unwind and the crank portions 33 and 4% swing downwardly and away from the lift gate 14 to aid the operator in moving the lift gate 14 to its open position, as shown in FIGURE 4. When the lift gate reaches its open position, shoulders 54 of the links engage the crank portions 33 and all of the torque rods to provide limit stops and prevent the toggles provided by the crank portions and the links from approaching a dead center position. In the open position of the lift gate the toggles provide a strut holding the lift gate in this position. The shoulders 54 are provided by lateral strengthening flanges ss integral with the links 44.

When the lift gate is moved to a closed position, the fact that the toggles are not fully aligned aids the operator in folding the toggles against the action of the torque Patented Aug. 1%, 1965 rods 13 and 29 to move the lift gate 14 to a closed position.

Referring now particularly to FIGURES 6 through 8 of the drawings, another embodiment of this invention will be described in like numerals will be used for like parts.

In this embodiment of the invention, the lift gate 14 is mounted on the body by suitable hinge means 53 located at each side thereof for swinging movement between a closed position, as shown in FIGURE 6, and an open position, as shown in FIGURE 7. A pair of torque rods wand 62 are located within the lift gate 14, with the bent ends 64 of the rods being respectively anchored on walls 26 and 23 of the lift gate 14, and the oppositely disposed crank ends 66 of the rods being respectively located outwardly of and adjacent walls 2t; and 26 of the lift gate and terminating in short lateral end portions 68. A pair of like mounting brackets 7 ti and 71 are respectively secured to the walls 26 and 28 inwardly of the lift gate, each bracket including a lateral slotted portion 72 and a lateral notched flange 74. The flange 72 of bracket 71 receives and journals one end of rod 62, with the bent end 64 of the rod being adjustably anchored in flange 74 thereof. The flange 72 of bracket 70 receives and journals one end of rod 6%, with the bent end of the rod being adjustably anchored in the flange 74 thereof The other end of rod 6d extends outwardly through aligned openings in bracket 71 and wall 28, While the other end of rod 62 extends outwardly through aligned openings in bracket 7% and wall 26.

The end portions 68 of the torque rods are pivotally connected to the lower ends of links 76, the upper ends of which are respectively pivotal'ly secured at '78 to the spaced hinge means 58, although they may be pivotally secured to mounting brackets mounted on the side walls of the opening 12 if desired.

When the liftgate 14 is in a closed position, as shown in FIGURE 6, the toggles which comprise the links 76 and the crank portions 66 of the torque rods, are located in a partially folded position, and as the lift gate is moved to an open position, as shown in FIGURE 7, the toggles unfold as the links 76 swing rearwardly and upwardly of the body and the crank portions 66 of the torque rods swing rearwardly and upwardly of the lift gate 14. It will be noted that the links 76 and the crank portions 66 are arranged so that the toggles comprised thereof do not reach a fully unfolded aligned relationship but rather are limited in their movement to a partially unfolded relationship to provide for ease of movement of the lift gate from its open position to its closed position. In the open posi- .tion of the lift gate the toggles provide a strut holding the lift gate in this position. It will also be noted that this embodiment differs from the first embodiment of the invention in that the links 76 and the crank port-ions 66 are located immediately adjacent the side walls 26 and 28 of the lift gate in theirunfolded position so as to be disposed in an out-of-the-way position with respect to the opening of the body to increase ease of ingress and egress to and from the body.

This embodiment of the invention has a further advantage over the first embodiment in that less stress load;

is placed on the hinge means 58 in the closed position of the lift gate to increase the life thereof. In the first embodiment of the invention, with reference to FIGURE 3, the crank ends 38 of the torque rods act to swing the links 44 inwardly of the body when the lift gate is in a closed position and there is nothing to limit this moveinent other than the lift gate itself. Accordingly, the bent ends 38 act to shift the links 44 downwardly and in turn "shift the lift gate 14 downwardly of the body toward the lower wall of the opening 12 to thereby place considerable stress on the hinge means 16. In the embodiment of the invention shown in FIGURES 6 through 8, the crank ends 66 of the torque rods tend to shift the links 76v upwardly of the body and inasmuch as the upper ends of these links are pivoted either to the body hinge bracket or to a support bracket mounted on the side walls of the opening 12, the force is taken by the body rather than by the lift gate to thus reduce the stress which is placed on the hinge means.

Thus, this invention provides a new and improved counterbalance assembly.

I claim:

1. in a vehicle body having an opening therein, a closure for said opening, hinge means swingably mounting said closure adjacent an edge portion thereof on said body for movement between open and closed positions with respect to said opening, said closure including a wall located in generally juxtaposed relationship to a wall of said opening in the closed position thereof, an elongated torsion member, means anchoring said member adjacent one end thereof to said closure, said member extending outwardly of said closure wall and including a laterally extending crank portion, a link member pivotally connected adjacent one end thereof to said crank portion and adjacent the other end thereof to said body, said crank portion and said link member providing a toggle interconnecting said closure and said body, said crank portion and link member. being located intermediate said juxtaposed walls and within said opening in a folded position relative to each other in the. closed position of said closure, said torsion member being torsional-1y stressed to swing the crank portion thereof relative to said closure and swing said link member outwardly of said opening upon movement of said closure to open position to locate said crank portion and link member in an unfolded position relative to each other wherein said crank portion and link member provide a strut extending outwardly of said opening and resiliently holding said closure in open position.

2. The structure recited in claim 1 wherein said crank portion and said link member swing in opposite directions as said closure moves to said open position thereof.

3. The structure recited in claim 1 wherein said link member is pivoted on said body adjacent said hinge means and said link member and crank portion are positioned adjacent said closure in the open position thereof and the unfolded position of said crank portion and link member.

4. The structure recited in claim 1 wherein said link member is pivoted on said body adjacent said hinge means, said crank portion biases said link member relative to said juxtaposed walls and toward said hinge means, and said link member and crank portion are positioned adjacent said closure in the open position thereof and the unfolded position of said link member and crank portion.

5. In a vehicle body having an opening therein, a closure for said opening, hinge means swingably rnounting said closure adjacent the upper edge portion thereof on said body for movement between open and closed positions with respect to said opening, said closure including side walls located in generally juxtaposed relationship to side walls of said opening in the closed position thereof, an elongated torsion member, means anchoring said member adjacent one end thereof to one of said closure side walls, said member extending outwardly of the other of said closure walls and including a'crank portion extending laterally thereof along-said otherclosure wall, a link member pivotally connectedadjacent one end thereof to said crank portion and adjacent the other end thereof to said body wall respective to said other closure wall, said crank portion and said link member providing a toggle interconnect-ing said'closu re and said body, said crank portion and link member being located intermediate said other closure wall and respective body wall and within said opening in a folded position relative to each other in the closed position of said closure,said torsion member being, torsionally stressed to swingv the crank portion thereof relative'to said other closure wall and swing said link member outwardly of said opening and said respective body wall upon movement of said closure to open position to locate said crank port-ion and link member in an unfolded position relative to each other and provide a strut interconnecting said closure and said body and resiliently holding said closure in said open position.

6. The structure recited in claim 1 wherein said link member and said crank portion are located generally juxtaposed to each other in the closed position of said closure and said link member is pivoted to said body adjacent the torsional axis of said torsion member.

7. The structure recited in claim 1 wherein said crank portion and link member extend generally upwardly of said body in the closed position of said closure member and said torsion member biases said link member outwardly of said body opening.

References Cited by the Examiner UNITED STATES PATENTS 2,070,046 2/ 37 Gredell 296--106 2,647,788 8/53 Kaiser et a1 296106 X 2,831,219 4/58 Nelson 2016 FOREIGN PATENTS 1,087,110 2/55 France.

A. HARRY LEVY, Primary Examiner. 

1. IN A VEHICLE BODY HAVING AN OPENING THEREIN, A CLOSURE FOR SAID OPENING, HINGE MENS SWINGABLY MOUNTING SAID CLOSURE ADJACENT AND EDGE PORTION THEREOF ON SAID BODY FOR MOVEMENT BETWEEN OPEN AND CLOSED POSITIONS WITH RESPECT TO SAID OPENING, SAID CLOSURE INCLUDING A WALL LOCATED IN GENERALLY JUXTAPOSED RELATIONSHIP TO A WALL OF SAID OPENING IN THE CLOSED POSITON THEREOF, AN ELONGATED TORSION MEMBER, MEANS ANCHORING SAID MEMBER ADJACENT ONE END THEREOF TO SAID CLOSURE, SAID MEMBER EXTENDING OUTWARDLY OF SAID CLOSURE WALL AND INCLUDING A LATERALLY EXTENDING CRANK PORTION, A LINK MEMBER PIVOTALLY CONNECTED ADJACENT ONE END THEREOF TO SAID CRNAK PORTION AND ADJACENT THE OTHER END THEREOF TO SAID BODY, SAID CRANK PORTION AND SAID LINK MEMBER PROVIDING A TOGGLE INTERCONNECTING SAID CLOSURE AND SAID BODY, SAID CRANK PORTION AND LINK MEMBER BEING LOCATED INTERMEDIATE SAID JUXTA- 